Natural weathering promoted the recovery of microbial community in bauxite residues

Purpose Natural weathering process increased microbial diversity and in bauxite residue. However, the its effect on the microbial metabolic activities is still poorly understood. Methods In this study, residue samples with different weathering time were collected to evaluate the microbial metabolic activities and community structure in bauxite residue. Results Community level physiological profiles (CLPP) results indicated that natural weathering process significantly increased the microbial metabolic activities and changed microbial carbon resources utilization pattern. The microbial metabolic diversity index increased from 2.68 to 3.29 and the average well color development increased from 0.41 to 1.47. The Shannon diversity significantly increased from 5.79 to 6.26 and the observed OTU numbers increased from 1009 to 1331, respectively. The relative abundance of Proteobacteria, Bacteroidota, Acidobacteria, Actinobacteria and Chloroflexi significantly increased following long term weathering process. Random forest model showed that Beijerinckiaceae, Rhizobiaceae, Microscillaceae, Caulobacteraceae, Sphingomonadaceae, Nitrospiraceae and Chitinophagaceae were the core species in the promotion of microbial metabolic activities. Redundancy analysis (RDA) indicated that the development of microbial communities was signifianltly affected by MWD followed by pH, TOC, AP, TN, EC and AN. Conclusions Natural weathering process could increase microbial metabolic activities and diversity, thus promote the recovery of microbial community in bauxite residue. Beijerinckiaceae, Rhizobiaceae, Microscillaceae, Caulobacteraceae, Sphingomonadaceae, Nitrospiraceae and Chitinophagaceae played vital roles in the promotion of microbial carbon metabolism in bauxite residue. Our results emphasize the significance of specific functional microbial species in the recovery of microbial communities in bauxite residue disposal areas.